I am some months into a retrofit of a Mazak machining center with Centroid controller and have become stuck on driving the AC servo spindle motor.
General googling suggested using a VFD for the spindle motor. I have tried two VFDs, both designed for permanent magnet motors. Sure they can run the motor at high speed but that's about it. At low speed they stall and jerk, most likely due to lack of encoder input. They have so little torque at 200 RPM that you can stop the spindle with one finger! I have spent months with ABB support and in the end they finally said, no, you need an AC servo drive. I kind of knew that all along but the internet said a VFD that does PM motors would do. They are much cheaper so I gave it a go.
Anyways, so now I need an AC servo drive for the spindle motor. Seems easy enough but I just cant find one that suits. The biggest issue is that most use a proprietary serial encoder signal and don't support incremental encoder input.
They only option I have found is from Kollmorgan which is pretty pricey. More than the oak and all three DYN4s combined! Metronix might also be an option but I never get a reply to my request for quotes. DMM and ABB options are too small. Yaskawa, Delta, Mitsubishi all have special encoder interface. Digitax has no encoder ouptut to the Centroid controller, but maybe I could share the signals.
The motor is a 200V,1.5kW nominal, 1.9kW 10 min 6000RPM Panasonic with 2500 PPM incremental encoder and hall commutation signals.
Does anyone know of a servo drive that is at least 2.2kW output power, 15A output, 200V 1/3 phase input, incremental encoder input, emulated encoder output, analog input, analog output, min 400 Hz output???